K. Eric Drexler, founder of the field first known simply as nanotechnology, then as molecular nanotechnology, and now as molecular manufacturing, has raised a bit of a ruckus within the advanced nanotech community.
On his new blog, Metamodern, Drexler openly challenges the assumption that diamond mechanosynthesis (using mechanical means to combine carbon atoms into diamond molecules, then make structures, and eventually products) is a good first step for researchers to pursue.
Eric uses forceful language to indicate his frustration:
[D]iamond is in many ways a true wonder-material... Diamond does, however, have a grave shortcoming: synthesis has been, and continues to be, difficult and expensive. Stubbornly so.
The methods I’m familiar with require either high temperatures and ultrahigh pressures, or highly reactive gas-phase species interacting with a hot surface in a vacuum chamber. Neither process is suited to atomically precise control. Advanced mechanosynthetic methods (of the sort analyzed in Chapter 8 of Nanosystems) will eventually erase this problem, but the emphasis here is on the words “advanced” and “eventually”...
Considering the difficulties of diamond synthesis, why treat diamond mechanosynthesis as if it were a necessary first step toward molecular manufacturing? Building a tiny bit of diamond this way would of course be an impressive lab demo, but the plausible technologies for achieving this seem difficult to extend, and I doubt that they would be very useful in any general sense.
It appears that Eric is actively trying to distance himself from those advocating the early pursuit of diamond mechanosynthesis, even as he acknowledges that the ideas he now objects to are drawn from his own writings. (This is reminiscent of his partially successful attempt to disown grey goo, an effort that hasn't worked entirely and in fact has backfired in some ways; various journalists act as though Drexler is simultaneously withdrawing all his early ideas concerning nanotech, not just his worries about out-of-control replicators.)
In response, Robert A. Freitas Jr. and Ralph Merkle, founders of the Nanofactory Collaboration and former colleagues of Drexler, quickly restated their commitment to the diamond mechanosynthesis approach by stating:
Our assessment is that diamondoid mechanosynthesis (DMS), including highly-parallelized atomically-precise diamondoid fabrication, is the quickest currently feasible route to a mature molecular nanotechnology, including nanofactories.
We do not think that DMS is a “necessary first step” for molecular manufacturing, and we wish the best of luck to those pursuing other paths. However, we do think DMS is a highly desirable first step, since it offers a much faster route to mature nanosystems than competing approaches. We disagree with the statement that “diamond synthesis seems almost irrelevant to progress toward advanced nanosystems.” We have a favorable view of the feasibility of the direct-to-DMS approach – a favorable view supported by hundreds of pages of detailed analysis in recently-published peer-reviewed technical journal papers and by gradually-evolving mainstream opinion.
CRN is, and always has been, neutral on whether "direct-to-DMS" is more or less likely to succeed than other approaches. Our focus remains on the implications of exponential general-purpose molecular manufacturing, whenever and however it is achieved. We're closely monitoring progress toward that end in as many areas as we can follow and will keep you posted if this current controversy results in any sort of new agreements or clarification on goals and methods.